In this paper a technique based on high-speed digital photography and the digital speckle correlation （DSC） method is used for the quantitative measurement of the displacement and strain fields of various Portevin L...In this paper a technique based on high-speed digital photography and the digital speckle correlation （DSC） method is used for the quantitative measurement of the displacement and strain fields of various Portevin Le Chatelier （PLC） bands （types A, B, and C）. The experimental results clearly show the nucleation process of a type-B band and the propagation of a type-A band. The results also reveal that there exists an elastic shrinkage deformation outside a PLC band during a large avalanche-like deformation inside the PLC band.展开更多
An efficient discrete singular convolution (DSC) method is introduced to the numerical solutions of incompressible Euler and Navier-Stokes equations with periodic boundary conditions. Two numerical tests of two-dimens...An efficient discrete singular convolution (DSC) method is introduced to the numerical solutions of incompressible Euler and Navier-Stokes equations with periodic boundary conditions. Two numerical tests of two-dimensional Navier-Stokes equations with periodic boundary conditions and Euler equations for doubly periodic shear layer flows are carried out by using the DSC method for spatial derivatives and fourth-order Runge-Kutta method for time advancement, respectively. The computational results show that the DSC method is efficient and robust for solving tho problems of incompressible flows, and has the potential of being extended to numerically solve much broader problems in fluid dynamics.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant Nos 1023030 and 10372098）.
文摘In this paper a technique based on high-speed digital photography and the digital speckle correlation （DSC） method is used for the quantitative measurement of the displacement and strain fields of various Portevin Le Chatelier （PLC） bands （types A, B, and C）. The experimental results clearly show the nucleation process of a type-B band and the propagation of a type-A band. The results also reveal that there exists an elastic shrinkage deformation outside a PLC band during a large avalanche-like deformation inside the PLC band.
基金The project supported by the National Natural Science Foundation of China(No.19902010)
文摘An efficient discrete singular convolution (DSC) method is introduced to the numerical solutions of incompressible Euler and Navier-Stokes equations with periodic boundary conditions. Two numerical tests of two-dimensional Navier-Stokes equations with periodic boundary conditions and Euler equations for doubly periodic shear layer flows are carried out by using the DSC method for spatial derivatives and fourth-order Runge-Kutta method for time advancement, respectively. The computational results show that the DSC method is efficient and robust for solving tho problems of incompressible flows, and has the potential of being extended to numerically solve much broader problems in fluid dynamics.
